Different types of wireless access systems have been developed to provide different types of services and capabilities. Some examples of wireless access systems include wireless local area networks (WLANs), (such as IEEE 802-based networks), and cellular networks, (such as UMTS terrestrial radio access network (UTRAN), a global system for mobile communication (GSM)/enhanced data rate for GSM evolution (EDGE) radio access network (GERAN), or the like). Each of these networks have been developed and tailored to provide specific applications.
Proposals for an E-UTRAN (Long Term Evolution for UTRAN and evolved Node-B (E-Node-B)) have been made to improve wireless system capacity and enhance performance. The E-UTRAN will provide significant advantages over existing wireless communication systems and additional services may be available through the higher bit rate and lower latency provided by the E-UTRAN. FIG. 1 shows a conventional integrated wireless communication system 100 including an E-UTRAN 114. The system 100 includes an access system stratum 110, a network stratum 120 and a multimedia stratum 130. The access system stratum 110 includes a plurality of radio access networks (RANs) 111-115, a core network (CN) 116 and an evolved CN 117. The RANs 111-115 include a generic access network (GAN) 111, a GERAN 112, a UTRAN 113, an E-UTRAN 114 and an interworking wireless local area network (I-WLAN) 115. The RANs 111-115 are connected to the CN 116 or the evolved CN 117 to provide services, (such as multimedia services from an Internet protocol (IP) multimedia subsystem (IMS) 131), to one or more WTRUs while interacting with an authentication, authorization and accounting (AAA) server 121, a mobile IP (MIP) server 122, or other network entities in the network stratum 120 via a gateway general packet radio services (GPRS) support node (GGSN) 118 or a packet data gateway (PDG) 119.
Currently, multimode wireless transmit/receive units (WTRUs) configured to support multiple wireless communication systems are available. The capabilities of each of the WTRUs may vary. For example, some WTRUs may support only UMTS, while other WTRUs may support multiple mode of operations such as I-WLAN, GERAN, and/or E-UTRAN. The WTRUs that are capable of supporting E-UTRAN will also be available in the future.
Therefore, it would be desirable to provide a method and system for supporting an E-UTRAN such that the WTRUs may receive and utilize such additional E-UTRAN capabilities and services.